1. Technical Field
The present invention relates to 3-oxo-pyridazine compounds and their use as B1-receptor antagonists, pharmaceutical compositions containing these compounds and methods of using them for the prevention or treatment of acute pain, visceral pain, neuropathic pain, inflammatory pain and pain receptor-mediated pain, tumour pain and headaches.
2. Prior Art
Compounds with a B1-antagonistic activity have already been described in International Patent Application PCT/EP2010/052232 or in the priority application on which it is based.
One aim of the present invention was to provide new compounds which are suitable in particular as pharmaceutical active substances that can be used for the treatment of diseases at least partly mediated by the B1 receptor.
An essential structural feature of the new compounds is the 6-oxo-1,6-dihydro-pyridazine-4-carboxylic acid amide group that is present in tautomeric equilibrium with the 6-hydroxy-pyridazine-4-carboxylic acid amide group:

Compared with the compounds from the prior art, the new substances are characterised in that they exhibit a strong B1-receptor blocking activity and at the same time have improved metabolic stability.